Evaluation of somaclonal variation in two rice varieties under different culture periods using morphological and genetic approaches

Abstract

Plants strive to maintain their existence and genetics through both generative and vegetative propagation. Tissue culture is one of the promising vegetative propagation methods that exploits the totipotency of plants to produce high-quality plants effectively. However, during the culture process, some anomalies often occur; one of the most common is somaclonal variation, which results from genetic mutations caused by carcinogenic hormones like 2,4-D, the genetic background of different rice varieties, and the period of the plant culture. The study was conducted using two varieties, namely the indica variety Ketan Hetam and the japonica Koshikari, each cultured on N6 medium containing the 2,4-D hormone for two, four, and six weeks. They were then regenerated in MS medium containing NAA and Kinetin. The resulting plantlets were analyzed using the RAPD method with four primers to detect the level of genetic mutation. The results of the study indicated that the indica rice variety Ketan Hitam had a lower regeneration rate than the japonica rice variety Koshihikari, particularly under treatments with longer culture periods, which may be associated with cell senescence that prevented callus regeneration into plantlets. However, Ketan Hitam exhibited greater genetic stability than Koshihikari.Keywords: genetic mutation; RAPD; tissue culture; somaclonal variation